The number of reported cases of domestic targeted email attacks containing viruses totaled 6,027 last year, including over 5,000 in the second half of the year alone, police said Thursday.
Some 90 percent of the email addresses attacked were not publicly available, indicating that senders researched their targets in advance, the National Police Agency said.
Some 60 percent of files attached to the emails were compressed, with Microsoft Word and Excel files accounting for about 30 percent and 10 percent of them, respectively.
There were 37 reported cases of attacks using the WannaCry ransomware, a computer worm that caused global disruption in May last year. No financial damage has been reported in the country, according to the NPA.
Through cooperation with the private sector, the NPA plans to gather more information about the dark web, a hidden network of Internet sites that allow users to communicate anonymously, in order to look into how information about cyberattack tools and security vulnerabilities are being exchanged online, officials said.